@Lucas - I commented on one of your facebook posts, but may want to modify the above and/or add additional information
1. You state that a radiator is included but I believe you mean the parallel condenser along with the condenser/radiator fan, both of which mount in front of the radiator currently in the car, which does not need changing for your retrofit. Are you including a means to mount the condenser into the car as well as mount the fan?
2. When advertising this outside of the forum, for the aluminum you may want to put a link to oilsdesigngroup.com since sometimes non-forum members have difficulty accessing older forum posts
3. You've included a fan belt but it is critical for people to know that the pulley on their harmonic balancer may need to be changed to accommodate powering the Sanden compressor. My car is a Euro 1972 CSi and did NOT come with AC, so in order to retrofit AC I would need to upgrade that pulley to allow for that additional belt location. This isn't a HARD job to do, but a full retrofit would include that pulley as well. I'm not suggesting you add that into your package but may be worthwhile to make a mention of this required part.
4. Given the system as you've designed it the choice of refrigerant may be up to the end user but I suspect you designed it for R134A? May be worth including that information. Does the set come with a full set of installation instructions? This obviously could be installed by many of us here on the forum, but we are perhaps the "tip of the spear" when it comes to what we are willing to take on given the numerous restoration projects included in these pages. For the average E9 owner, and for your advertising, I would suggest including a link to installation instructions or the comment "We recommend installation by a person experienced with E9s", etc. Since the TXV valve is contained within the evaporator housing, installation here is a bit of a three-part process - install the basic components mechanical and plumbing components into the vehicle but don't install any side panels or trim, bring the vehicle to radiator shop for filling of refrigerant and checking of all hose connections, then finishing the installation of the side pieces, gear shift console, etc.
5. Is your vision that the side console pieces and gear shift console are installed as-is or are you imagining that purchasers will cover them in vinyl locally? Your biggest competition for this kit retrofit is obviously the Oldenzaal kit, which comes at a significant cost over your option and doesn't necessarily have some of the "upgrades" of 3-position fan, separate relays and fuses, etc, but does include fully finished side consoles and a gearshift console. Your summary is a bit vague on this, suggesting that in the future you may offer it covered but not currently...
My points/questions above are not meant as criticisms - I am sincerely impressed at what you've put together. I hope that you are able to sell lots of these (and of course will be entering the photo contest - just thinking up good photo ideas!) and so am approaching this as "what would I want to know if I were a buyer"